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-   -   What caused this blue cast? KM 7D (

BillS22 Oct 1, 2005 8:43 PM

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This is an unprocessed photo I shot in RAW, 1/40, F5.6, Natural +, 200 ISO all the rest auto.

The lighting was late afternoon, very cloudy with black clouds and a chance of rain.

Minnie doesn't have blue fur :-)

I can get most of the blue out by adjusting the temperature up witha RAW editor.

Should I have used dirrerent camera settings? Flash maybe?



BillS22 Oct 1, 2005 8:56 PM

ooops dirrerent = different

:?I flunked typing

nooner Oct 1, 2005 9:06 PM

JimC Oct 2, 2005 3:35 PM

White Balance information is stored in the raw file. But, your raw converter must use it.

In fact, I took the time to find and send David Coffin (author of dcraw.c) .mrw files of photos taken of Macbeth Color Charts in Sunlight to help make sure he got the white balance just right for the new KM 5D (especially since I'm interested in this model for personal use). ;-)

Someone in Thailand with a pre-production KM 5D was kind enough to take the photos at my request.

WB information is stored with your 7D .mrw files, too. It's basically some RGB multipliers stored in the metadata.

Are you sure you were using Auto White Balance?

If so, are you sure your raw converter isn't set to ignore the camera's white balance information? If you're using ACR, select "As Shot" to use it.

The Flash more closely approximates daylight. The darker overcast conditions could have made a difference. But, it's unlikely it's turning the fur blue where it should be white. The Auto White Balance may even be taking flash into consideration if you use it, and adjusting the white balance accordingly.

What are you using to convert the images?

JimC Oct 2, 2005 4:38 PM

nooner wrote:

WB is not controlled by the camera when using RAW.
See my post above on this issue.

If you're trying to use a third party raw converter with your 5D and it's not seeing the as shot white balance information, it's probably because it doesn't *really* support the 5D yet.I've seen some users trying to use hex editors to replace 7D with 5D in raw converters to get them to work with the 5D, and some may work without this hack.

But,if they don't officially support this model,then they're not going to see things like theas shot white balance, due to some differences in the metadata.

If you want a copy of dcraw.c to play with, already compiled for Windows, I can send you a copy of it. Just send me a PM with an e-mail address, and I'll send it via a service like (in case your e-mail or ISP doesn't like .exe file attachments).

The service sends you an e-mail with a link to download it, instead of attaching it to the e-mail. If you use dcraw with the -w option, it will use the camera's white balance info when converting your images. It doesn't have the sliders, etc., you'll find in a converter with a GUI. But, the new demosaic algorithms David started using with newer dcraw.c versions are pretty good.

A lot of raw converters base their software, at least in part,on David's code.

So, more and more of them should be supporting the 5D soon (and many othersdo have more features and a Graphical Interface).

BillS22 Oct 3, 2005 12:48 AM

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Here's what the RAW file looks like per ACR, As shot, no processing....

BillS22 Oct 3, 2005 12:50 AM

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After processing with Minolta's DiMAGE, adjust temperature, sharpening, and just a little Color correction, I think this is more true... and YES my camera is on AWB.

Even the fence behind the subject has less blue....

JimC Oct 3, 2005 3:34 PM

Well... I dunno.

It's a tad underexposed, and it's not uncommon to see whites look a bit gray when this happens, which can be interpreted as being a bit cool. It's better to err towards underexposure to protect highlight detail.

Also, the last edit looks a bit warm for dark skies and overcast conditions. I like a warmer look better, but it's not necessarily more accurate. ;-)

I really don't see a strong blue cast to it where the fur is concerned (I thought you had already edited the image you originally posted when you said the fur was "blue" and you got most of it out). But,I haven't tried using an eyedropper with an editor to measure it or anything.

I see what you're talking about (in the fence in particular I some gray/blue areas). Ditto for something else white in the background. These do seem to have a bit of a cast to them (whichmight be differences in the lighting between the flash and the background).

It'sjust not what I expected you meant (I was expecting a strong blue cast when you mentioned blue fur). Is your monitor calibrated? What do you get shooting raw+jpeg (are the Jpeg images the same way)?

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